Merge tag 'iommu-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
[linux/fpc-iii.git] / net / batman-adv / network-coding.c
blob0cec108b7a99f0805a1c19822bf04385a0c6fa23
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2012-2020 B.A.T.M.A.N. contributors:
4 * Martin Hundebøll, Jeppe Ledet-Pedersen
5 */
7 #include "network-coding.h"
8 #include "main.h"
10 #include <linux/atomic.h>
11 #include <linux/bitops.h>
12 #include <linux/byteorder/generic.h>
13 #include <linux/compiler.h>
14 #include <linux/errno.h>
15 #include <linux/etherdevice.h>
16 #include <linux/gfp.h>
17 #include <linux/if_ether.h>
18 #include <linux/if_packet.h>
19 #include <linux/init.h>
20 #include <linux/jhash.h>
21 #include <linux/jiffies.h>
22 #include <linux/kernel.h>
23 #include <linux/kref.h>
24 #include <linux/list.h>
25 #include <linux/lockdep.h>
26 #include <linux/net.h>
27 #include <linux/netdevice.h>
28 #include <linux/prandom.h>
29 #include <linux/printk.h>
30 #include <linux/rculist.h>
31 #include <linux/rcupdate.h>
32 #include <linux/skbuff.h>
33 #include <linux/slab.h>
34 #include <linux/spinlock.h>
35 #include <linux/stddef.h>
36 #include <linux/string.h>
37 #include <linux/workqueue.h>
38 #include <uapi/linux/batadv_packet.h>
40 #include "hash.h"
41 #include "log.h"
42 #include "originator.h"
43 #include "routing.h"
44 #include "send.h"
45 #include "tvlv.h"
47 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
48 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
50 static void batadv_nc_worker(struct work_struct *work);
51 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
52 struct batadv_hard_iface *recv_if);
54 /**
55 * batadv_nc_init() - one-time initialization for network coding
57 * Return: 0 on success or negative error number in case of failure
59 int __init batadv_nc_init(void)
61 int ret;
63 /* Register our packet type */
64 ret = batadv_recv_handler_register(BATADV_CODED,
65 batadv_nc_recv_coded_packet);
67 return ret;
70 /**
71 * batadv_nc_start_timer() - initialise the nc periodic worker
72 * @bat_priv: the bat priv with all the soft interface information
74 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
76 queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
77 msecs_to_jiffies(10));
80 /**
81 * batadv_nc_tvlv_container_update() - update the network coding tvlv container
82 * after network coding setting change
83 * @bat_priv: the bat priv with all the soft interface information
85 static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
87 char nc_mode;
89 nc_mode = atomic_read(&bat_priv->network_coding);
91 switch (nc_mode) {
92 case 0:
93 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
94 break;
95 case 1:
96 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
97 NULL, 0);
98 break;
103 * batadv_nc_status_update() - update the network coding tvlv container after
104 * network coding setting change
105 * @net_dev: the soft interface net device
107 void batadv_nc_status_update(struct net_device *net_dev)
109 struct batadv_priv *bat_priv = netdev_priv(net_dev);
111 batadv_nc_tvlv_container_update(bat_priv);
115 * batadv_nc_tvlv_ogm_handler_v1() - process incoming nc tvlv container
116 * @bat_priv: the bat priv with all the soft interface information
117 * @orig: the orig_node of the ogm
118 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
119 * @tvlv_value: tvlv buffer containing the gateway data
120 * @tvlv_value_len: tvlv buffer length
122 static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
123 struct batadv_orig_node *orig,
124 u8 flags,
125 void *tvlv_value, u16 tvlv_value_len)
127 if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
128 clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
129 else
130 set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
134 * batadv_nc_mesh_init() - initialise coding hash table and start housekeeping
135 * @bat_priv: the bat priv with all the soft interface information
137 * Return: 0 on success or negative error number in case of failure
139 int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
141 bat_priv->nc.timestamp_fwd_flush = jiffies;
142 bat_priv->nc.timestamp_sniffed_purge = jiffies;
144 if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
145 return 0;
147 bat_priv->nc.coding_hash = batadv_hash_new(128);
148 if (!bat_priv->nc.coding_hash)
149 goto err;
151 batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
152 &batadv_nc_coding_hash_lock_class_key);
154 bat_priv->nc.decoding_hash = batadv_hash_new(128);
155 if (!bat_priv->nc.decoding_hash)
156 goto err;
158 batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
159 &batadv_nc_decoding_hash_lock_class_key);
161 INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
162 batadv_nc_start_timer(bat_priv);
164 batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
165 NULL, BATADV_TVLV_NC, 1,
166 BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
167 batadv_nc_tvlv_container_update(bat_priv);
168 return 0;
170 err:
171 return -ENOMEM;
175 * batadv_nc_init_bat_priv() - initialise the nc specific bat_priv variables
176 * @bat_priv: the bat priv with all the soft interface information
178 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
180 atomic_set(&bat_priv->network_coding, 0);
181 bat_priv->nc.min_tq = 200;
182 bat_priv->nc.max_fwd_delay = 10;
183 bat_priv->nc.max_buffer_time = 200;
187 * batadv_nc_init_orig() - initialise the nc fields of an orig_node
188 * @orig_node: the orig_node which is going to be initialised
190 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
192 INIT_LIST_HEAD(&orig_node->in_coding_list);
193 INIT_LIST_HEAD(&orig_node->out_coding_list);
194 spin_lock_init(&orig_node->in_coding_list_lock);
195 spin_lock_init(&orig_node->out_coding_list_lock);
199 * batadv_nc_node_release() - release nc_node from lists and queue for free
200 * after rcu grace period
201 * @ref: kref pointer of the nc_node
203 static void batadv_nc_node_release(struct kref *ref)
205 struct batadv_nc_node *nc_node;
207 nc_node = container_of(ref, struct batadv_nc_node, refcount);
209 batadv_orig_node_put(nc_node->orig_node);
210 kfree_rcu(nc_node, rcu);
214 * batadv_nc_node_put() - decrement the nc_node refcounter and possibly
215 * release it
216 * @nc_node: nc_node to be free'd
218 static void batadv_nc_node_put(struct batadv_nc_node *nc_node)
220 kref_put(&nc_node->refcount, batadv_nc_node_release);
224 * batadv_nc_path_release() - release nc_path from lists and queue for free
225 * after rcu grace period
226 * @ref: kref pointer of the nc_path
228 static void batadv_nc_path_release(struct kref *ref)
230 struct batadv_nc_path *nc_path;
232 nc_path = container_of(ref, struct batadv_nc_path, refcount);
234 kfree_rcu(nc_path, rcu);
238 * batadv_nc_path_put() - decrement the nc_path refcounter and possibly
239 * release it
240 * @nc_path: nc_path to be free'd
242 static void batadv_nc_path_put(struct batadv_nc_path *nc_path)
244 kref_put(&nc_path->refcount, batadv_nc_path_release);
248 * batadv_nc_packet_free() - frees nc packet
249 * @nc_packet: the nc packet to free
250 * @dropped: whether the packet is freed because is dropped
252 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet,
253 bool dropped)
255 if (dropped)
256 kfree_skb(nc_packet->skb);
257 else
258 consume_skb(nc_packet->skb);
260 batadv_nc_path_put(nc_packet->nc_path);
261 kfree(nc_packet);
265 * batadv_nc_to_purge_nc_node() - checks whether an nc node has to be purged
266 * @bat_priv: the bat priv with all the soft interface information
267 * @nc_node: the nc node to check
269 * Return: true if the entry has to be purged now, false otherwise
271 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
272 struct batadv_nc_node *nc_node)
274 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
275 return true;
277 return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
281 * batadv_nc_to_purge_nc_path_coding() - checks whether an nc path has timed out
282 * @bat_priv: the bat priv with all the soft interface information
283 * @nc_path: the nc path to check
285 * Return: true if the entry has to be purged now, false otherwise
287 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
288 struct batadv_nc_path *nc_path)
290 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
291 return true;
293 /* purge the path when no packets has been added for 10 times the
294 * max_fwd_delay time
296 return batadv_has_timed_out(nc_path->last_valid,
297 bat_priv->nc.max_fwd_delay * 10);
301 * batadv_nc_to_purge_nc_path_decoding() - checks whether an nc path has timed
302 * out
303 * @bat_priv: the bat priv with all the soft interface information
304 * @nc_path: the nc path to check
306 * Return: true if the entry has to be purged now, false otherwise
308 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
309 struct batadv_nc_path *nc_path)
311 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
312 return true;
314 /* purge the path when no packets has been added for 10 times the
315 * max_buffer time
317 return batadv_has_timed_out(nc_path->last_valid,
318 bat_priv->nc.max_buffer_time * 10);
322 * batadv_nc_purge_orig_nc_nodes() - go through list of nc nodes and purge stale
323 * entries
324 * @bat_priv: the bat priv with all the soft interface information
325 * @list: list of nc nodes
326 * @lock: nc node list lock
327 * @to_purge: function in charge to decide whether an entry has to be purged or
328 * not. This function takes the nc node as argument and has to return
329 * a boolean value: true if the entry has to be deleted, false
330 * otherwise
332 static void
333 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
334 struct list_head *list,
335 spinlock_t *lock,
336 bool (*to_purge)(struct batadv_priv *,
337 struct batadv_nc_node *))
339 struct batadv_nc_node *nc_node, *nc_node_tmp;
341 /* For each nc_node in list */
342 spin_lock_bh(lock);
343 list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
344 /* if an helper function has been passed as parameter,
345 * ask it if the entry has to be purged or not
347 if (to_purge && !to_purge(bat_priv, nc_node))
348 continue;
350 batadv_dbg(BATADV_DBG_NC, bat_priv,
351 "Removing nc_node %pM -> %pM\n",
352 nc_node->addr, nc_node->orig_node->orig);
353 list_del_rcu(&nc_node->list);
354 batadv_nc_node_put(nc_node);
356 spin_unlock_bh(lock);
360 * batadv_nc_purge_orig() - purges all nc node data attached of the given
361 * originator
362 * @bat_priv: the bat priv with all the soft interface information
363 * @orig_node: orig_node with the nc node entries to be purged
364 * @to_purge: function in charge to decide whether an entry has to be purged or
365 * not. This function takes the nc node as argument and has to return
366 * a boolean value: true is the entry has to be deleted, false
367 * otherwise
369 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
370 struct batadv_orig_node *orig_node,
371 bool (*to_purge)(struct batadv_priv *,
372 struct batadv_nc_node *))
374 /* Check ingoing nc_node's of this orig_node */
375 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
376 &orig_node->in_coding_list_lock,
377 to_purge);
379 /* Check outgoing nc_node's of this orig_node */
380 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
381 &orig_node->out_coding_list_lock,
382 to_purge);
386 * batadv_nc_purge_orig_hash() - traverse entire originator hash to check if
387 * they have timed out nc nodes
388 * @bat_priv: the bat priv with all the soft interface information
390 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
392 struct batadv_hashtable *hash = bat_priv->orig_hash;
393 struct hlist_head *head;
394 struct batadv_orig_node *orig_node;
395 u32 i;
397 if (!hash)
398 return;
400 /* For each orig_node */
401 for (i = 0; i < hash->size; i++) {
402 head = &hash->table[i];
404 rcu_read_lock();
405 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
406 batadv_nc_purge_orig(bat_priv, orig_node,
407 batadv_nc_to_purge_nc_node);
408 rcu_read_unlock();
413 * batadv_nc_purge_paths() - traverse all nc paths part of the hash and remove
414 * unused ones
415 * @bat_priv: the bat priv with all the soft interface information
416 * @hash: hash table containing the nc paths to check
417 * @to_purge: function in charge to decide whether an entry has to be purged or
418 * not. This function takes the nc node as argument and has to return
419 * a boolean value: true is the entry has to be deleted, false
420 * otherwise
422 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
423 struct batadv_hashtable *hash,
424 bool (*to_purge)(struct batadv_priv *,
425 struct batadv_nc_path *))
427 struct hlist_head *head;
428 struct hlist_node *node_tmp;
429 struct batadv_nc_path *nc_path;
430 spinlock_t *lock; /* Protects lists in hash */
431 u32 i;
433 for (i = 0; i < hash->size; i++) {
434 head = &hash->table[i];
435 lock = &hash->list_locks[i];
437 /* For each nc_path in this bin */
438 spin_lock_bh(lock);
439 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
440 /* if an helper function has been passed as parameter,
441 * ask it if the entry has to be purged or not
443 if (to_purge && !to_purge(bat_priv, nc_path))
444 continue;
446 /* purging an non-empty nc_path should never happen, but
447 * is observed under high CPU load. Delay the purging
448 * until next iteration to allow the packet_list to be
449 * emptied first.
451 if (!unlikely(list_empty(&nc_path->packet_list))) {
452 net_ratelimited_function(printk,
453 KERN_WARNING
454 "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
455 nc_path->prev_hop,
456 nc_path->next_hop);
457 continue;
460 /* nc_path is unused, so remove it */
461 batadv_dbg(BATADV_DBG_NC, bat_priv,
462 "Remove nc_path %pM -> %pM\n",
463 nc_path->prev_hop, nc_path->next_hop);
464 hlist_del_rcu(&nc_path->hash_entry);
465 batadv_nc_path_put(nc_path);
467 spin_unlock_bh(lock);
472 * batadv_nc_hash_key_gen() - computes the nc_path hash key
473 * @key: buffer to hold the final hash key
474 * @src: source ethernet mac address going into the hash key
475 * @dst: destination ethernet mac address going into the hash key
477 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
478 const char *dst)
480 memcpy(key->prev_hop, src, sizeof(key->prev_hop));
481 memcpy(key->next_hop, dst, sizeof(key->next_hop));
485 * batadv_nc_hash_choose() - compute the hash value for an nc path
486 * @data: data to hash
487 * @size: size of the hash table
489 * Return: the selected index in the hash table for the given data.
491 static u32 batadv_nc_hash_choose(const void *data, u32 size)
493 const struct batadv_nc_path *nc_path = data;
494 u32 hash = 0;
496 hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
497 hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
499 return hash % size;
503 * batadv_nc_hash_compare() - comparing function used in the network coding hash
504 * tables
505 * @node: node in the local table
506 * @data2: second object to compare the node to
508 * Return: true if the two entry are the same, false otherwise
510 static bool batadv_nc_hash_compare(const struct hlist_node *node,
511 const void *data2)
513 const struct batadv_nc_path *nc_path1, *nc_path2;
515 nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
516 nc_path2 = data2;
518 /* Return 1 if the two keys are identical */
519 if (!batadv_compare_eth(nc_path1->prev_hop, nc_path2->prev_hop))
520 return false;
522 if (!batadv_compare_eth(nc_path1->next_hop, nc_path2->next_hop))
523 return false;
525 return true;
529 * batadv_nc_hash_find() - search for an existing nc path and return it
530 * @hash: hash table containing the nc path
531 * @data: search key
533 * Return: the nc_path if found, NULL otherwise.
535 static struct batadv_nc_path *
536 batadv_nc_hash_find(struct batadv_hashtable *hash,
537 void *data)
539 struct hlist_head *head;
540 struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
541 int index;
543 if (!hash)
544 return NULL;
546 index = batadv_nc_hash_choose(data, hash->size);
547 head = &hash->table[index];
549 rcu_read_lock();
550 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
551 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
552 continue;
554 if (!kref_get_unless_zero(&nc_path->refcount))
555 continue;
557 nc_path_tmp = nc_path;
558 break;
560 rcu_read_unlock();
562 return nc_path_tmp;
566 * batadv_nc_send_packet() - send non-coded packet and free nc_packet struct
567 * @nc_packet: the nc packet to send
569 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
571 batadv_send_unicast_skb(nc_packet->skb, nc_packet->neigh_node);
572 nc_packet->skb = NULL;
573 batadv_nc_packet_free(nc_packet, false);
577 * batadv_nc_sniffed_purge() - Checks timestamp of given sniffed nc_packet.
578 * @bat_priv: the bat priv with all the soft interface information
579 * @nc_path: the nc path the packet belongs to
580 * @nc_packet: the nc packet to be checked
582 * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
583 * timeout. If so, the packet is no longer kept and the entry deleted from the
584 * queue. Has to be called with the appropriate locks.
586 * Return: false as soon as the entry in the fifo queue has not been timed out
587 * yet and true otherwise.
589 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
590 struct batadv_nc_path *nc_path,
591 struct batadv_nc_packet *nc_packet)
593 unsigned long timeout = bat_priv->nc.max_buffer_time;
594 bool res = false;
596 lockdep_assert_held(&nc_path->packet_list_lock);
598 /* Packets are added to tail, so the remaining packets did not time
599 * out and we can stop processing the current queue
601 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
602 !batadv_has_timed_out(nc_packet->timestamp, timeout))
603 goto out;
605 /* purge nc packet */
606 list_del(&nc_packet->list);
607 batadv_nc_packet_free(nc_packet, true);
609 res = true;
611 out:
612 return res;
616 * batadv_nc_fwd_flush() - Checks the timestamp of the given nc packet.
617 * @bat_priv: the bat priv with all the soft interface information
618 * @nc_path: the nc path the packet belongs to
619 * @nc_packet: the nc packet to be checked
621 * Checks whether the given nc packet has hit its forward timeout. If so, the
622 * packet is no longer delayed, immediately sent and the entry deleted from the
623 * queue. Has to be called with the appropriate locks.
625 * Return: false as soon as the entry in the fifo queue has not been timed out
626 * yet and true otherwise.
628 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
629 struct batadv_nc_path *nc_path,
630 struct batadv_nc_packet *nc_packet)
632 unsigned long timeout = bat_priv->nc.max_fwd_delay;
634 lockdep_assert_held(&nc_path->packet_list_lock);
636 /* Packets are added to tail, so the remaining packets did not time
637 * out and we can stop processing the current queue
639 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
640 !batadv_has_timed_out(nc_packet->timestamp, timeout))
641 return false;
643 /* Send packet */
644 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
645 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
646 nc_packet->skb->len + ETH_HLEN);
647 list_del(&nc_packet->list);
648 batadv_nc_send_packet(nc_packet);
650 return true;
654 * batadv_nc_process_nc_paths() - traverse given nc packet pool and free timed
655 * out nc packets
656 * @bat_priv: the bat priv with all the soft interface information
657 * @hash: to be processed hash table
658 * @process_fn: Function called to process given nc packet. Should return true
659 * to encourage this function to proceed with the next packet.
660 * Otherwise the rest of the current queue is skipped.
662 static void
663 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
664 struct batadv_hashtable *hash,
665 bool (*process_fn)(struct batadv_priv *,
666 struct batadv_nc_path *,
667 struct batadv_nc_packet *))
669 struct hlist_head *head;
670 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
671 struct batadv_nc_path *nc_path;
672 bool ret;
673 int i;
675 if (!hash)
676 return;
678 /* Loop hash table bins */
679 for (i = 0; i < hash->size; i++) {
680 head = &hash->table[i];
682 /* Loop coding paths */
683 rcu_read_lock();
684 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
685 /* Loop packets */
686 spin_lock_bh(&nc_path->packet_list_lock);
687 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
688 &nc_path->packet_list, list) {
689 ret = process_fn(bat_priv, nc_path, nc_packet);
690 if (!ret)
691 break;
693 spin_unlock_bh(&nc_path->packet_list_lock);
695 rcu_read_unlock();
700 * batadv_nc_worker() - periodic task for housekeeping related to network
701 * coding
702 * @work: kernel work struct
704 static void batadv_nc_worker(struct work_struct *work)
706 struct delayed_work *delayed_work;
707 struct batadv_priv_nc *priv_nc;
708 struct batadv_priv *bat_priv;
709 unsigned long timeout;
711 delayed_work = to_delayed_work(work);
712 priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
713 bat_priv = container_of(priv_nc, struct batadv_priv, nc);
715 batadv_nc_purge_orig_hash(bat_priv);
716 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
717 batadv_nc_to_purge_nc_path_coding);
718 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
719 batadv_nc_to_purge_nc_path_decoding);
721 timeout = bat_priv->nc.max_fwd_delay;
723 if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
724 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
725 batadv_nc_fwd_flush);
726 bat_priv->nc.timestamp_fwd_flush = jiffies;
729 if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
730 bat_priv->nc.max_buffer_time)) {
731 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
732 batadv_nc_sniffed_purge);
733 bat_priv->nc.timestamp_sniffed_purge = jiffies;
736 /* Schedule a new check */
737 batadv_nc_start_timer(bat_priv);
741 * batadv_can_nc_with_orig() - checks whether the given orig node is suitable
742 * for coding or not
743 * @bat_priv: the bat priv with all the soft interface information
744 * @orig_node: neighboring orig node which may be used as nc candidate
745 * @ogm_packet: incoming ogm packet also used for the checks
747 * Return: true if:
748 * 1) The OGM must have the most recent sequence number.
749 * 2) The TTL must be decremented by one and only one.
750 * 3) The OGM must be received from the first hop from orig_node.
751 * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
753 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
754 struct batadv_orig_node *orig_node,
755 struct batadv_ogm_packet *ogm_packet)
757 struct batadv_orig_ifinfo *orig_ifinfo;
758 u32 last_real_seqno;
759 u8 last_ttl;
761 orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
762 if (!orig_ifinfo)
763 return false;
765 last_ttl = orig_ifinfo->last_ttl;
766 last_real_seqno = orig_ifinfo->last_real_seqno;
767 batadv_orig_ifinfo_put(orig_ifinfo);
769 if (last_real_seqno != ntohl(ogm_packet->seqno))
770 return false;
771 if (last_ttl != ogm_packet->ttl + 1)
772 return false;
773 if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
774 return false;
775 if (ogm_packet->tq < bat_priv->nc.min_tq)
776 return false;
778 return true;
782 * batadv_nc_find_nc_node() - search for an existing nc node and return it
783 * @orig_node: orig node originating the ogm packet
784 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
785 * (can be equal to orig_node)
786 * @in_coding: traverse incoming or outgoing network coding list
788 * Return: the nc_node if found, NULL otherwise.
790 static struct batadv_nc_node *
791 batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
792 struct batadv_orig_node *orig_neigh_node,
793 bool in_coding)
795 struct batadv_nc_node *nc_node, *nc_node_out = NULL;
796 struct list_head *list;
798 if (in_coding)
799 list = &orig_neigh_node->in_coding_list;
800 else
801 list = &orig_neigh_node->out_coding_list;
803 /* Traverse list of nc_nodes to orig_node */
804 rcu_read_lock();
805 list_for_each_entry_rcu(nc_node, list, list) {
806 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
807 continue;
809 if (!kref_get_unless_zero(&nc_node->refcount))
810 continue;
812 /* Found a match */
813 nc_node_out = nc_node;
814 break;
816 rcu_read_unlock();
818 return nc_node_out;
822 * batadv_nc_get_nc_node() - retrieves an nc node or creates the entry if it was
823 * not found
824 * @bat_priv: the bat priv with all the soft interface information
825 * @orig_node: orig node originating the ogm packet
826 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
827 * (can be equal to orig_node)
828 * @in_coding: traverse incoming or outgoing network coding list
830 * Return: the nc_node if found or created, NULL in case of an error.
832 static struct batadv_nc_node *
833 batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
834 struct batadv_orig_node *orig_node,
835 struct batadv_orig_node *orig_neigh_node,
836 bool in_coding)
838 struct batadv_nc_node *nc_node;
839 spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
840 struct list_head *list;
842 /* Select ingoing or outgoing coding node */
843 if (in_coding) {
844 lock = &orig_neigh_node->in_coding_list_lock;
845 list = &orig_neigh_node->in_coding_list;
846 } else {
847 lock = &orig_neigh_node->out_coding_list_lock;
848 list = &orig_neigh_node->out_coding_list;
851 spin_lock_bh(lock);
853 /* Check if nc_node is already added */
854 nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
856 /* Node found */
857 if (nc_node)
858 goto unlock;
860 nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
861 if (!nc_node)
862 goto unlock;
864 /* Initialize nc_node */
865 INIT_LIST_HEAD(&nc_node->list);
866 kref_init(&nc_node->refcount);
867 ether_addr_copy(nc_node->addr, orig_node->orig);
868 kref_get(&orig_neigh_node->refcount);
869 nc_node->orig_node = orig_neigh_node;
871 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
872 nc_node->addr, nc_node->orig_node->orig);
874 /* Add nc_node to orig_node */
875 kref_get(&nc_node->refcount);
876 list_add_tail_rcu(&nc_node->list, list);
878 unlock:
879 spin_unlock_bh(lock);
881 return nc_node;
885 * batadv_nc_update_nc_node() - updates stored incoming and outgoing nc node
886 * structs (best called on incoming OGMs)
887 * @bat_priv: the bat priv with all the soft interface information
888 * @orig_node: orig node originating the ogm packet
889 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
890 * (can be equal to orig_node)
891 * @ogm_packet: incoming ogm packet
892 * @is_single_hop_neigh: orig_node is a single hop neighbor
894 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
895 struct batadv_orig_node *orig_node,
896 struct batadv_orig_node *orig_neigh_node,
897 struct batadv_ogm_packet *ogm_packet,
898 int is_single_hop_neigh)
900 struct batadv_nc_node *in_nc_node = NULL;
901 struct batadv_nc_node *out_nc_node = NULL;
903 /* Check if network coding is enabled */
904 if (!atomic_read(&bat_priv->network_coding))
905 goto out;
907 /* check if orig node is network coding enabled */
908 if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
909 goto out;
911 /* accept ogms from 'good' neighbors and single hop neighbors */
912 if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
913 !is_single_hop_neigh)
914 goto out;
916 /* Add orig_node as in_nc_node on hop */
917 in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
918 orig_neigh_node, true);
919 if (!in_nc_node)
920 goto out;
922 in_nc_node->last_seen = jiffies;
924 /* Add hop as out_nc_node on orig_node */
925 out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
926 orig_node, false);
927 if (!out_nc_node)
928 goto out;
930 out_nc_node->last_seen = jiffies;
932 out:
933 if (in_nc_node)
934 batadv_nc_node_put(in_nc_node);
935 if (out_nc_node)
936 batadv_nc_node_put(out_nc_node);
940 * batadv_nc_get_path() - get existing nc_path or allocate a new one
941 * @bat_priv: the bat priv with all the soft interface information
942 * @hash: hash table containing the nc path
943 * @src: ethernet source address - first half of the nc path search key
944 * @dst: ethernet destination address - second half of the nc path search key
946 * Return: pointer to nc_path if the path was found or created, returns NULL
947 * on error.
949 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
950 struct batadv_hashtable *hash,
951 u8 *src,
952 u8 *dst)
954 int hash_added;
955 struct batadv_nc_path *nc_path, nc_path_key;
957 batadv_nc_hash_key_gen(&nc_path_key, src, dst);
959 /* Search for existing nc_path */
960 nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
962 if (nc_path) {
963 /* Set timestamp to delay removal of nc_path */
964 nc_path->last_valid = jiffies;
965 return nc_path;
968 /* No existing nc_path was found; create a new */
969 nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
971 if (!nc_path)
972 return NULL;
974 /* Initialize nc_path */
975 INIT_LIST_HEAD(&nc_path->packet_list);
976 spin_lock_init(&nc_path->packet_list_lock);
977 kref_init(&nc_path->refcount);
978 nc_path->last_valid = jiffies;
979 ether_addr_copy(nc_path->next_hop, dst);
980 ether_addr_copy(nc_path->prev_hop, src);
982 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
983 nc_path->prev_hop,
984 nc_path->next_hop);
986 /* Add nc_path to hash table */
987 kref_get(&nc_path->refcount);
988 hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
989 batadv_nc_hash_choose, &nc_path_key,
990 &nc_path->hash_entry);
992 if (hash_added < 0) {
993 kfree(nc_path);
994 return NULL;
997 return nc_path;
1001 * batadv_nc_random_weight_tq() - scale the receivers TQ-value to avoid unfair
1002 * selection of a receiver with slightly lower TQ than the other
1003 * @tq: to be weighted tq value
1005 * Return: scaled tq value
1007 static u8 batadv_nc_random_weight_tq(u8 tq)
1009 /* randomize the estimated packet loss (max TQ - estimated TQ) */
1010 u8 rand_tq = prandom_u32_max(BATADV_TQ_MAX_VALUE + 1 - tq);
1012 /* convert to (randomized) estimated tq again */
1013 return BATADV_TQ_MAX_VALUE - rand_tq;
1017 * batadv_nc_memxor() - XOR destination with source
1018 * @dst: byte array to XOR into
1019 * @src: byte array to XOR from
1020 * @len: length of destination array
1022 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1024 unsigned int i;
1026 for (i = 0; i < len; ++i)
1027 dst[i] ^= src[i];
1031 * batadv_nc_code_packets() - code a received unicast_packet with an nc packet
1032 * into a coded_packet and send it
1033 * @bat_priv: the bat priv with all the soft interface information
1034 * @skb: data skb to forward
1035 * @ethhdr: pointer to the ethernet header inside the skb
1036 * @nc_packet: structure containing the packet to the skb can be coded with
1037 * @neigh_node: next hop to forward packet to
1039 * Return: true if both packets are consumed, false otherwise.
1041 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1042 struct sk_buff *skb,
1043 struct ethhdr *ethhdr,
1044 struct batadv_nc_packet *nc_packet,
1045 struct batadv_neigh_node *neigh_node)
1047 u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1048 struct sk_buff *skb_dest, *skb_src;
1049 struct batadv_unicast_packet *packet1;
1050 struct batadv_unicast_packet *packet2;
1051 struct batadv_coded_packet *coded_packet;
1052 struct batadv_neigh_node *neigh_tmp, *router_neigh, *first_dest;
1053 struct batadv_neigh_node *router_coding = NULL, *second_dest;
1054 struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1055 struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1056 u8 *first_source, *second_source;
1057 __be32 packet_id1, packet_id2;
1058 size_t count;
1059 bool res = false;
1060 int coding_len;
1061 int unicast_size = sizeof(*packet1);
1062 int coded_size = sizeof(*coded_packet);
1063 int header_add = coded_size - unicast_size;
1065 /* TODO: do we need to consider the outgoing interface for
1066 * coded packets?
1068 router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1069 BATADV_IF_DEFAULT);
1070 if (!router_neigh)
1071 goto out;
1073 router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1074 BATADV_IF_DEFAULT);
1075 if (!router_neigh_ifinfo)
1076 goto out;
1078 neigh_tmp = nc_packet->neigh_node;
1079 router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1080 BATADV_IF_DEFAULT);
1081 if (!router_coding)
1082 goto out;
1084 router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1085 BATADV_IF_DEFAULT);
1086 if (!router_coding_ifinfo)
1087 goto out;
1089 tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1090 tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1091 tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1092 tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1094 /* Select one destination for the MAC-header dst-field based on
1095 * weighted TQ-values.
1097 if (tq_weighted_neigh >= tq_weighted_coding) {
1098 /* Destination from nc_packet is selected for MAC-header */
1099 first_dest = nc_packet->neigh_node;
1100 first_source = nc_packet->nc_path->prev_hop;
1101 second_dest = neigh_node;
1102 second_source = ethhdr->h_source;
1103 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1104 packet2 = (struct batadv_unicast_packet *)skb->data;
1105 packet_id1 = nc_packet->packet_id;
1106 packet_id2 = batadv_skb_crc32(skb,
1107 skb->data + sizeof(*packet2));
1108 } else {
1109 /* Destination for skb is selected for MAC-header */
1110 first_dest = neigh_node;
1111 first_source = ethhdr->h_source;
1112 second_dest = nc_packet->neigh_node;
1113 second_source = nc_packet->nc_path->prev_hop;
1114 packet1 = (struct batadv_unicast_packet *)skb->data;
1115 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1116 packet_id1 = batadv_skb_crc32(skb,
1117 skb->data + sizeof(*packet1));
1118 packet_id2 = nc_packet->packet_id;
1121 /* Instead of zero padding the smallest data buffer, we
1122 * code into the largest.
1124 if (skb->len <= nc_packet->skb->len) {
1125 skb_dest = nc_packet->skb;
1126 skb_src = skb;
1127 } else {
1128 skb_dest = skb;
1129 skb_src = nc_packet->skb;
1132 /* coding_len is used when decoding the packet shorter packet */
1133 coding_len = skb_src->len - unicast_size;
1135 if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1136 goto out;
1138 skb_push(skb_dest, header_add);
1140 coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1141 skb_reset_mac_header(skb_dest);
1143 coded_packet->packet_type = BATADV_CODED;
1144 coded_packet->version = BATADV_COMPAT_VERSION;
1145 coded_packet->ttl = packet1->ttl;
1147 /* Info about first unicast packet */
1148 ether_addr_copy(coded_packet->first_source, first_source);
1149 ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1150 coded_packet->first_crc = packet_id1;
1151 coded_packet->first_ttvn = packet1->ttvn;
1153 /* Info about second unicast packet */
1154 ether_addr_copy(coded_packet->second_dest, second_dest->addr);
1155 ether_addr_copy(coded_packet->second_source, second_source);
1156 ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1157 coded_packet->second_crc = packet_id2;
1158 coded_packet->second_ttl = packet2->ttl;
1159 coded_packet->second_ttvn = packet2->ttvn;
1160 coded_packet->coded_len = htons(coding_len);
1162 /* This is where the magic happens: Code skb_src into skb_dest */
1163 batadv_nc_memxor(skb_dest->data + coded_size,
1164 skb_src->data + unicast_size, coding_len);
1166 /* Update counters accordingly */
1167 if (BATADV_SKB_CB(skb_src)->decoded &&
1168 BATADV_SKB_CB(skb_dest)->decoded) {
1169 /* Both packets are recoded */
1170 count = skb_src->len + ETH_HLEN;
1171 count += skb_dest->len + ETH_HLEN;
1172 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1173 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1174 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1175 !BATADV_SKB_CB(skb_dest)->decoded) {
1176 /* Both packets are newly coded */
1177 count = skb_src->len + ETH_HLEN;
1178 count += skb_dest->len + ETH_HLEN;
1179 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1180 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1181 } else if (BATADV_SKB_CB(skb_src)->decoded &&
1182 !BATADV_SKB_CB(skb_dest)->decoded) {
1183 /* skb_src recoded and skb_dest is newly coded */
1184 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1185 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1186 skb_src->len + ETH_HLEN);
1187 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1188 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1189 skb_dest->len + ETH_HLEN);
1190 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1191 BATADV_SKB_CB(skb_dest)->decoded) {
1192 /* skb_src is newly coded and skb_dest is recoded */
1193 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1194 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1195 skb_src->len + ETH_HLEN);
1196 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1197 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1198 skb_dest->len + ETH_HLEN);
1201 /* skb_src is now coded into skb_dest, so free it */
1202 consume_skb(skb_src);
1204 /* avoid duplicate free of skb from nc_packet */
1205 nc_packet->skb = NULL;
1206 batadv_nc_packet_free(nc_packet, false);
1208 /* Send the coded packet and return true */
1209 batadv_send_unicast_skb(skb_dest, first_dest);
1210 res = true;
1211 out:
1212 if (router_neigh)
1213 batadv_neigh_node_put(router_neigh);
1214 if (router_coding)
1215 batadv_neigh_node_put(router_coding);
1216 if (router_neigh_ifinfo)
1217 batadv_neigh_ifinfo_put(router_neigh_ifinfo);
1218 if (router_coding_ifinfo)
1219 batadv_neigh_ifinfo_put(router_coding_ifinfo);
1220 return res;
1224 * batadv_nc_skb_coding_possible() - true if a decoded skb is available at dst.
1225 * @skb: data skb to forward
1226 * @dst: destination mac address of the other skb to code with
1227 * @src: source mac address of skb
1229 * Whenever we network code a packet we have to check whether we received it in
1230 * a network coded form. If so, we may not be able to use it for coding because
1231 * some neighbors may also have received (overheard) the packet in the network
1232 * coded form without being able to decode it. It is hard to know which of the
1233 * neighboring nodes was able to decode the packet, therefore we can only
1234 * re-code the packet if the source of the previous encoded packet is involved.
1235 * Since the source encoded the packet we can be certain it has all necessary
1236 * decode information.
1238 * Return: true if coding of a decoded packet is allowed.
1240 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1242 if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1243 return false;
1244 return true;
1248 * batadv_nc_path_search() - Find the coding path matching in_nc_node and
1249 * out_nc_node to retrieve a buffered packet that can be used for coding.
1250 * @bat_priv: the bat priv with all the soft interface information
1251 * @in_nc_node: pointer to skb next hop's neighbor nc node
1252 * @out_nc_node: pointer to skb source's neighbor nc node
1253 * @skb: data skb to forward
1254 * @eth_dst: next hop mac address of skb
1256 * Return: true if coding of a decoded skb is allowed.
1258 static struct batadv_nc_packet *
1259 batadv_nc_path_search(struct batadv_priv *bat_priv,
1260 struct batadv_nc_node *in_nc_node,
1261 struct batadv_nc_node *out_nc_node,
1262 struct sk_buff *skb,
1263 u8 *eth_dst)
1265 struct batadv_nc_path *nc_path, nc_path_key;
1266 struct batadv_nc_packet *nc_packet_out = NULL;
1267 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1268 struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1269 int idx;
1271 if (!hash)
1272 return NULL;
1274 /* Create almost path key */
1275 batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1276 out_nc_node->addr);
1277 idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1279 /* Check for coding opportunities in this nc_path */
1280 rcu_read_lock();
1281 hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1282 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1283 continue;
1285 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1286 continue;
1288 spin_lock_bh(&nc_path->packet_list_lock);
1289 if (list_empty(&nc_path->packet_list)) {
1290 spin_unlock_bh(&nc_path->packet_list_lock);
1291 continue;
1294 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1295 &nc_path->packet_list, list) {
1296 if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1297 eth_dst,
1298 in_nc_node->addr))
1299 continue;
1301 /* Coding opportunity is found! */
1302 list_del(&nc_packet->list);
1303 nc_packet_out = nc_packet;
1304 break;
1307 spin_unlock_bh(&nc_path->packet_list_lock);
1308 break;
1310 rcu_read_unlock();
1312 return nc_packet_out;
1316 * batadv_nc_skb_src_search() - Loops through the list of neighboring nodes of
1317 * the skb's sender (may be equal to the originator).
1318 * @bat_priv: the bat priv with all the soft interface information
1319 * @skb: data skb to forward
1320 * @eth_dst: next hop mac address of skb
1321 * @eth_src: source mac address of skb
1322 * @in_nc_node: pointer to skb next hop's neighbor nc node
1324 * Return: an nc packet if a suitable coding packet was found, NULL otherwise.
1326 static struct batadv_nc_packet *
1327 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1328 struct sk_buff *skb,
1329 u8 *eth_dst,
1330 u8 *eth_src,
1331 struct batadv_nc_node *in_nc_node)
1333 struct batadv_orig_node *orig_node;
1334 struct batadv_nc_node *out_nc_node;
1335 struct batadv_nc_packet *nc_packet = NULL;
1337 orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1338 if (!orig_node)
1339 return NULL;
1341 rcu_read_lock();
1342 list_for_each_entry_rcu(out_nc_node,
1343 &orig_node->out_coding_list, list) {
1344 /* Check if the skb is decoded and if recoding is possible */
1345 if (!batadv_nc_skb_coding_possible(skb,
1346 out_nc_node->addr, eth_src))
1347 continue;
1349 /* Search for an opportunity in this nc_path */
1350 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1351 out_nc_node, skb, eth_dst);
1352 if (nc_packet)
1353 break;
1355 rcu_read_unlock();
1357 batadv_orig_node_put(orig_node);
1358 return nc_packet;
1362 * batadv_nc_skb_store_before_coding() - set the ethernet src and dst of the
1363 * unicast skb before it is stored for use in later decoding
1364 * @bat_priv: the bat priv with all the soft interface information
1365 * @skb: data skb to store
1366 * @eth_dst_new: new destination mac address of skb
1368 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1369 struct sk_buff *skb,
1370 u8 *eth_dst_new)
1372 struct ethhdr *ethhdr;
1374 /* Copy skb header to change the mac header */
1375 skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1376 if (!skb)
1377 return;
1379 /* Set the mac header as if we actually sent the packet uncoded */
1380 ethhdr = eth_hdr(skb);
1381 ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1382 ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1384 /* Set data pointer to MAC header to mimic packets from our tx path */
1385 skb_push(skb, ETH_HLEN);
1387 /* Add the packet to the decoding packet pool */
1388 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1390 /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1391 * our ref
1393 consume_skb(skb);
1397 * batadv_nc_skb_dst_search() - Loops through list of neighboring nodes to dst.
1398 * @skb: data skb to forward
1399 * @neigh_node: next hop to forward packet to
1400 * @ethhdr: pointer to the ethernet header inside the skb
1402 * Loops through the list of neighboring nodes the next hop has a good
1403 * connection to (receives OGMs with a sufficient quality). We need to find a
1404 * neighbor of our next hop that potentially sent a packet which our next hop
1405 * also received (overheard) and has stored for later decoding.
1407 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1409 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1410 struct batadv_neigh_node *neigh_node,
1411 struct ethhdr *ethhdr)
1413 struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1414 struct batadv_priv *bat_priv = netdev_priv(netdev);
1415 struct batadv_orig_node *orig_node = neigh_node->orig_node;
1416 struct batadv_nc_node *nc_node;
1417 struct batadv_nc_packet *nc_packet = NULL;
1419 rcu_read_lock();
1420 list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1421 /* Search for coding opportunity with this in_nc_node */
1422 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1423 neigh_node->addr,
1424 ethhdr->h_source, nc_node);
1426 /* Opportunity was found, so stop searching */
1427 if (nc_packet)
1428 break;
1430 rcu_read_unlock();
1432 if (!nc_packet)
1433 return false;
1435 /* Save packets for later decoding */
1436 batadv_nc_skb_store_before_coding(bat_priv, skb,
1437 neigh_node->addr);
1438 batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1439 nc_packet->neigh_node->addr);
1441 /* Code and send packets */
1442 if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1443 neigh_node))
1444 return true;
1446 /* out of mem ? Coding failed - we have to free the buffered packet
1447 * to avoid memleaks. The skb passed as argument will be dealt with
1448 * by the calling function.
1450 batadv_nc_send_packet(nc_packet);
1451 return false;
1455 * batadv_nc_skb_add_to_path() - buffer skb for later encoding / decoding
1456 * @skb: skb to add to path
1457 * @nc_path: path to add skb to
1458 * @neigh_node: next hop to forward packet to
1459 * @packet_id: checksum to identify packet
1461 * Return: true if the packet was buffered or false in case of an error.
1463 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1464 struct batadv_nc_path *nc_path,
1465 struct batadv_neigh_node *neigh_node,
1466 __be32 packet_id)
1468 struct batadv_nc_packet *nc_packet;
1470 nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1471 if (!nc_packet)
1472 return false;
1474 /* Initialize nc_packet */
1475 nc_packet->timestamp = jiffies;
1476 nc_packet->packet_id = packet_id;
1477 nc_packet->skb = skb;
1478 nc_packet->neigh_node = neigh_node;
1479 nc_packet->nc_path = nc_path;
1481 /* Add coding packet to list */
1482 spin_lock_bh(&nc_path->packet_list_lock);
1483 list_add_tail(&nc_packet->list, &nc_path->packet_list);
1484 spin_unlock_bh(&nc_path->packet_list_lock);
1486 return true;
1490 * batadv_nc_skb_forward() - try to code a packet or add it to the coding packet
1491 * buffer
1492 * @skb: data skb to forward
1493 * @neigh_node: next hop to forward packet to
1495 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1497 bool batadv_nc_skb_forward(struct sk_buff *skb,
1498 struct batadv_neigh_node *neigh_node)
1500 const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1501 struct batadv_priv *bat_priv = netdev_priv(netdev);
1502 struct batadv_unicast_packet *packet;
1503 struct batadv_nc_path *nc_path;
1504 struct ethhdr *ethhdr = eth_hdr(skb);
1505 __be32 packet_id;
1506 u8 *payload;
1508 /* Check if network coding is enabled */
1509 if (!atomic_read(&bat_priv->network_coding))
1510 goto out;
1512 /* We only handle unicast packets */
1513 payload = skb_network_header(skb);
1514 packet = (struct batadv_unicast_packet *)payload;
1515 if (packet->packet_type != BATADV_UNICAST)
1516 goto out;
1518 /* Try to find a coding opportunity and send the skb if one is found */
1519 if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1520 return true;
1522 /* Find or create a nc_path for this src-dst pair */
1523 nc_path = batadv_nc_get_path(bat_priv,
1524 bat_priv->nc.coding_hash,
1525 ethhdr->h_source,
1526 neigh_node->addr);
1528 if (!nc_path)
1529 goto out;
1531 /* Add skb to nc_path */
1532 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1533 if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1534 goto free_nc_path;
1536 /* Packet is consumed */
1537 return true;
1539 free_nc_path:
1540 batadv_nc_path_put(nc_path);
1541 out:
1542 /* Packet is not consumed */
1543 return false;
1547 * batadv_nc_skb_store_for_decoding() - save a clone of the skb which can be
1548 * used when decoding coded packets
1549 * @bat_priv: the bat priv with all the soft interface information
1550 * @skb: data skb to store
1552 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1553 struct sk_buff *skb)
1555 struct batadv_unicast_packet *packet;
1556 struct batadv_nc_path *nc_path;
1557 struct ethhdr *ethhdr = eth_hdr(skb);
1558 __be32 packet_id;
1559 u8 *payload;
1561 /* Check if network coding is enabled */
1562 if (!atomic_read(&bat_priv->network_coding))
1563 goto out;
1565 /* Check for supported packet type */
1566 payload = skb_network_header(skb);
1567 packet = (struct batadv_unicast_packet *)payload;
1568 if (packet->packet_type != BATADV_UNICAST)
1569 goto out;
1571 /* Find existing nc_path or create a new */
1572 nc_path = batadv_nc_get_path(bat_priv,
1573 bat_priv->nc.decoding_hash,
1574 ethhdr->h_source,
1575 ethhdr->h_dest);
1577 if (!nc_path)
1578 goto out;
1580 /* Clone skb and adjust skb->data to point at batman header */
1581 skb = skb_clone(skb, GFP_ATOMIC);
1582 if (unlikely(!skb))
1583 goto free_nc_path;
1585 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1586 goto free_skb;
1588 if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1589 goto free_skb;
1591 /* Add skb to nc_path */
1592 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1593 if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1594 goto free_skb;
1596 batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1597 return;
1599 free_skb:
1600 kfree_skb(skb);
1601 free_nc_path:
1602 batadv_nc_path_put(nc_path);
1603 out:
1604 return;
1608 * batadv_nc_skb_store_sniffed_unicast() - check if a received unicast packet
1609 * should be saved in the decoding buffer and, if so, store it there
1610 * @bat_priv: the bat priv with all the soft interface information
1611 * @skb: unicast skb to store
1613 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1614 struct sk_buff *skb)
1616 struct ethhdr *ethhdr = eth_hdr(skb);
1618 if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1619 return;
1621 /* Set data pointer to MAC header to mimic packets from our tx path */
1622 skb_push(skb, ETH_HLEN);
1624 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1628 * batadv_nc_skb_decode_packet() - decode given skb using the decode data stored
1629 * in nc_packet
1630 * @bat_priv: the bat priv with all the soft interface information
1631 * @skb: unicast skb to decode
1632 * @nc_packet: decode data needed to decode the skb
1634 * Return: pointer to decoded unicast packet if the packet was decoded or NULL
1635 * in case of an error.
1637 static struct batadv_unicast_packet *
1638 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1639 struct batadv_nc_packet *nc_packet)
1641 const int h_size = sizeof(struct batadv_unicast_packet);
1642 const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1643 struct batadv_unicast_packet *unicast_packet;
1644 struct batadv_coded_packet coded_packet_tmp;
1645 struct ethhdr *ethhdr, ethhdr_tmp;
1646 u8 *orig_dest, ttl, ttvn;
1647 unsigned int coding_len;
1648 int err;
1650 /* Save headers temporarily */
1651 memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1652 memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1654 if (skb_cow(skb, 0) < 0)
1655 return NULL;
1657 if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1658 return NULL;
1660 /* Data points to batman header, so set mac header 14 bytes before
1661 * and network to data
1663 skb_set_mac_header(skb, -ETH_HLEN);
1664 skb_reset_network_header(skb);
1666 /* Reconstruct original mac header */
1667 ethhdr = eth_hdr(skb);
1668 *ethhdr = ethhdr_tmp;
1670 /* Select the correct unicast header information based on the location
1671 * of our mac address in the coded_packet header
1673 if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1674 /* If we are the second destination the packet was overheard,
1675 * so the Ethernet address must be copied to h_dest and
1676 * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1678 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1679 skb->pkt_type = PACKET_HOST;
1681 orig_dest = coded_packet_tmp.second_orig_dest;
1682 ttl = coded_packet_tmp.second_ttl;
1683 ttvn = coded_packet_tmp.second_ttvn;
1684 } else {
1685 orig_dest = coded_packet_tmp.first_orig_dest;
1686 ttl = coded_packet_tmp.ttl;
1687 ttvn = coded_packet_tmp.first_ttvn;
1690 coding_len = ntohs(coded_packet_tmp.coded_len);
1692 if (coding_len > skb->len)
1693 return NULL;
1695 /* Here the magic is reversed:
1696 * extract the missing packet from the received coded packet
1698 batadv_nc_memxor(skb->data + h_size,
1699 nc_packet->skb->data + h_size,
1700 coding_len);
1702 /* Resize decoded skb if decoded with larger packet */
1703 if (nc_packet->skb->len > coding_len + h_size) {
1704 err = pskb_trim_rcsum(skb, coding_len + h_size);
1705 if (err)
1706 return NULL;
1709 /* Create decoded unicast packet */
1710 unicast_packet = (struct batadv_unicast_packet *)skb->data;
1711 unicast_packet->packet_type = BATADV_UNICAST;
1712 unicast_packet->version = BATADV_COMPAT_VERSION;
1713 unicast_packet->ttl = ttl;
1714 ether_addr_copy(unicast_packet->dest, orig_dest);
1715 unicast_packet->ttvn = ttvn;
1717 batadv_nc_packet_free(nc_packet, false);
1718 return unicast_packet;
1722 * batadv_nc_find_decoding_packet() - search through buffered decoding data to
1723 * find the data needed to decode the coded packet
1724 * @bat_priv: the bat priv with all the soft interface information
1725 * @ethhdr: pointer to the ethernet header inside the coded packet
1726 * @coded: coded packet we try to find decode data for
1728 * Return: pointer to nc packet if the needed data was found or NULL otherwise.
1730 static struct batadv_nc_packet *
1731 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1732 struct ethhdr *ethhdr,
1733 struct batadv_coded_packet *coded)
1735 struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1736 struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1737 struct batadv_nc_path *nc_path, nc_path_key;
1738 u8 *dest, *source;
1739 __be32 packet_id;
1740 int index;
1742 if (!hash)
1743 return NULL;
1745 /* Select the correct packet id based on the location of our mac-addr */
1746 dest = ethhdr->h_source;
1747 if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1748 source = coded->second_source;
1749 packet_id = coded->second_crc;
1750 } else {
1751 source = coded->first_source;
1752 packet_id = coded->first_crc;
1755 batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1756 index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1758 /* Search for matching coding path */
1759 rcu_read_lock();
1760 hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1761 /* Find matching nc_packet */
1762 spin_lock_bh(&nc_path->packet_list_lock);
1763 list_for_each_entry(tmp_nc_packet,
1764 &nc_path->packet_list, list) {
1765 if (packet_id == tmp_nc_packet->packet_id) {
1766 list_del(&tmp_nc_packet->list);
1768 nc_packet = tmp_nc_packet;
1769 break;
1772 spin_unlock_bh(&nc_path->packet_list_lock);
1774 if (nc_packet)
1775 break;
1777 rcu_read_unlock();
1779 if (!nc_packet)
1780 batadv_dbg(BATADV_DBG_NC, bat_priv,
1781 "No decoding packet found for %u\n", packet_id);
1783 return nc_packet;
1787 * batadv_nc_recv_coded_packet() - try to decode coded packet and enqueue the
1788 * resulting unicast packet
1789 * @skb: incoming coded packet
1790 * @recv_if: pointer to interface this packet was received on
1792 * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1793 * otherwise.
1795 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1796 struct batadv_hard_iface *recv_if)
1798 struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1799 struct batadv_unicast_packet *unicast_packet;
1800 struct batadv_coded_packet *coded_packet;
1801 struct batadv_nc_packet *nc_packet;
1802 struct ethhdr *ethhdr;
1803 int hdr_size = sizeof(*coded_packet);
1805 /* Check if network coding is enabled */
1806 if (!atomic_read(&bat_priv->network_coding))
1807 goto free_skb;
1809 /* Make sure we can access (and remove) header */
1810 if (unlikely(!pskb_may_pull(skb, hdr_size)))
1811 goto free_skb;
1813 coded_packet = (struct batadv_coded_packet *)skb->data;
1814 ethhdr = eth_hdr(skb);
1816 /* Verify frame is destined for us */
1817 if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1818 !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1819 goto free_skb;
1821 /* Update stat counter */
1822 if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1823 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1825 nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1826 coded_packet);
1827 if (!nc_packet) {
1828 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1829 goto free_skb;
1832 /* Make skb's linear, because decoding accesses the entire buffer */
1833 if (skb_linearize(skb) < 0)
1834 goto free_nc_packet;
1836 if (skb_linearize(nc_packet->skb) < 0)
1837 goto free_nc_packet;
1839 /* Decode the packet */
1840 unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1841 if (!unicast_packet) {
1842 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1843 goto free_nc_packet;
1846 /* Mark packet as decoded to do correct recoding when forwarding */
1847 BATADV_SKB_CB(skb)->decoded = true;
1848 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1849 batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1850 skb->len + ETH_HLEN);
1851 return batadv_recv_unicast_packet(skb, recv_if);
1853 free_nc_packet:
1854 batadv_nc_packet_free(nc_packet, true);
1855 free_skb:
1856 kfree_skb(skb);
1858 return NET_RX_DROP;
1862 * batadv_nc_mesh_free() - clean up network coding memory
1863 * @bat_priv: the bat priv with all the soft interface information
1865 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1867 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1868 batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1869 cancel_delayed_work_sync(&bat_priv->nc.work);
1871 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1872 batadv_hash_destroy(bat_priv->nc.coding_hash);
1873 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1874 batadv_hash_destroy(bat_priv->nc.decoding_hash);